AST/ALT ratio: what it shows about your liver and how to read it

The AST/ALT ratio divides one liver enzyme by another: aspartate aminotransferase (AST) by alanine aminotransferase (ALT). It is also called the De Ritis ratio, after the researcher who described it. The ratio adds most when one or both enzymes are raised, because the balance between them can hint at the cause of a liver problem and how far along it is.

What the two enzymes are

ALT sits mainly in liver cells and is found in low amounts elsewhere, so a raised ALT usually points to the liver. AST is found in the liver too, but also in skeletal muscle, heart muscle and blood cells. When liver cells are injured, both leak into the blood.

AST is cleared from the blood about twice as fast as ALT, with half-lives of roughly 18 and 36 hours. That difference is part of why the ratio shifts as a liver problem develops or settles.

How it is calculated

AST/ALT ratio = AST / ALT, with both enzymes in units per litre (U/L). For example, an AST of 24 U/L and an ALT of 30 U/L give a ratio of 0.8. The ratio has no unit.

Reading the ratio

There is no generally accepted reference range for the ratio. A 2013 review of its use explains why: healthy limits are hard to define when the ratio's main use is in people whose enzymes are already abnormal. The same review gives healthy upper limits of about 1.3 in men and 1.7 in women. The ratio runs higher in women even though both enzymes tend to be lower, and it also shifts with the laboratory's method. If your report prints a range for the ratio, that is the one to read your result against.

When the enzymes are raised, these are the patterns most often discussed:

Pattern	What it is usually associated with
Below 1, with ALT clearly raised	Fatty liver linked to weight and metabolism, and viral hepatitis; in acute viral hepatitis the ratio is often 0.5 to 0.7
Above 1, in a long-standing liver condition	More advanced scarring (fibrosis), which is why the ratio is built into fibrosis scores
Above 1.5 to 2, with AST raised	Often described with alcohol-related liver injury
High early on, falling towards 1 over a few days	Muscle injury, including after hard exercise

These are patterns, not diagnoses. Most people with alcohol-related liver disease have a ratio below 2, and many below 1, while a ratio slightly above 1 can appear in chronic viral hepatitis as scarring develops.

What a high ratio usually points to

When AST runs higher than ALT and both are raised, a doctor usually considers:

• Alcohol. AST tends to rise more than ALT in alcohol-related liver injury, partly because alcohol depletes vitamin B6, which ALT depends on.
• Scarring in a long-standing liver condition. In fatty liver disease or chronic viral hepatitis, a ratio above 1 is linked with more advanced fibrosis.
• Muscle. Hard exercise, a muscle injury or a muscle condition releases AST. Creatine kinase (CK) is the test that separates a muscle source from a liver one.
• The sample. AST is released from blood cells when a sample is haemolysed, which raises AST and the ratio artificially.

What a doctor typically looks at next: a repeat of the liver tests, GGT and a question about alcohol, CK if muscle is possible, a platelet count to calculate a fibrosis score, an ultrasound, and where scarring is a question, a second-line test such as an ELF blood test or elastography, a scan that measures liver stiffness.

What a low ratio usually points to

A ratio below 1 is the usual pattern when ALT is raised: fatty liver related to weight and metabolism, and viral hepatitis. When both enzymes are within range, a low ratio on its own carries little meaning.

What moves it

• Exercise. In a study of healthy men, one hour of weightlifting raised AST and ALT for at least seven days. AST tends to rise more after muscle strain. The same point appears in Comprehensive blood test in Dubai: what to expect.
• Alcohol in the days before the test. A high ratio can reflect recent drinking.
• Sample handling. Haemolysis raises AST and the ratio falsely.
• Laboratory method. Some laboratories add pyridoxal phosphate, the active form of vitamin B6, to the enzyme test and some do not. The difference matters most in people who are low in B6.
• Day-to-day variation. Within the same person, AST varies by about 14% and ALT by about 20% between tests, and in one study 30% of mildly raised results were normal on repeat.
• Medicines. Many medicines can affect liver enzymes, so the timing of any new medicine matters when a result is read.

Preparing for the test

Nothing is specific to the ratio. Avoid hard or unfamiliar exercise, especially weight training, in the days before. Follow the fasting instruction for the liver function test, and tell the person taking the sample about alcohol, medicines and supplements.

How Clare's panel handles it

Clare calculates the AST/ALT ratio from AST and ALT, which the lab measures. The ratio is AST divided by ALT, both in U/L.

Why it matters in the UAE

The ratio is built into fibrosis scores that doctors use to sort people with fatty liver by risk. A 2026 study at a diabetes centre in Dubai looked at 373 adults with type 2 diabetes, 93% of them UAE nationals, using two such scores: FIB-4, built from age, AST, ALT and platelets, and the NAFLD fibrosis score, which uses the AST/ALT ratio directly alongside albumin. Fatty liver was suspected, from imaging or raised liver enzymes, in 56% of patients, and 2.7% fell in the high-risk band for advanced scarring. Because it was a specialist clinic, the figures do not describe the whole UAE population; the authors suggest building these scores into routine diabetes care.

Price

The ratio is usually reported within a liver function test. Check that the test includes AST as well as ALT, since some liver panels report ALT alone. When we read public prices on 11 October 2026, a liver function test cost from 89 to 1,100 at six UAE providers; the top of that range was a hospital package that adds other tests. VAT is rarely stated, some are offer or "from" prices, and home collection can add a fee.

Related tests

The ratio is read with its two parts, AST and ALT, and with GGT, which helps when alcohol or medicines are in question. The platelet count from a CBC blood test joins AST and ALT in the FIB-4 score.

Why it means more over time

Because the enzymes vary from day to day, a single ratio is a weak signal, and abnormal liver tests are usually repeated and read against earlier results before anything is decided. A ratio that climbs above 1 over successive tests in someone with a long-standing liver condition is the kind of change that prompts a fibrosis assessment. How often it is repeated depends on why it was measured; in a yearly panel, it is read against last year's enzymes.

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